ATPase activity of KaiC determines the basic timing for circadian clock of cyanobacteria
ATPase activity of KaiC determines the basic timing for circadian clock of cyanobacteria
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DOI：
10.1073/pnas.0706292104
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发表时间：
2007-10-09
影响因子：
11.1
通讯作者：
Kondo, Takao
中科院分区：
文献类型：
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作者：
Terauchi, Kazuki;Kitayama, Yohko;Kondo, Takao
KaiC磷酸化的自我维持振荡已在体外重建，表明该周期是蓝藻生物钟的基本时间发生器。我们发现KaiC的ATP酶活性满足昼夜振荡、周期长度和温度补偿的特征。KaiC具有极弱但稳定的ATP酶活性（每天15个ATP分子），并且KaiA和KaiB的添加使得活性在体外以昼夜节律周期振荡。KaiC的ATP酶活性本质上是温度不变的，这表明昼夜节律周期的温度补偿可以由这种简单的生化反应驱动。此外，野生型KaiC和五个周期突变蛋白的活性与其体内昼夜节律频率成正比，表明ATP酶活性定义了昼夜节律周期。因此，我们建议，KaiC ATP酶活性构成的最基本的反应，在蓝藻的昼夜节律周期性。
Self-sustainable oscillation of KaiC phosphorylation has been reconstituted in vitro, demonstrating that this cycle is the basic time generator of the circadian clock of cyanobacteria. Here we show that the ATPase activity of KaiC satisfies the characteristics of the circadian oscillation, the period length, and the temperature compensation. KaiC possesses extremely weak but stable ATPase activity (15 molecules of ATP per day), and the addition of KaiA and KaiB makes the activity oscillate with a circadian period in vitro. The ATPase activity of KaiC is inherently temperature-invariant, suggesting that temperature compensation of the circadian period could be driven by this simple biochemical reaction. Moreover, the activities of wild-type KaiC and five period-mutant proteins are directly proportional to their in vivo circadian frequencies, indicating that the ATPase activity defines the circadian period. Thus, we propose that KaiC ATPase activity constitutes the most fundamental reaction underlying circadian periodicity in cyanobacteria.